In this tutorial, I explain the test code provided in the "Getting Started with BlueJ" article.

Two core concepts of a PulpCore applet are the Stage and the Scene.

The Stage is where an applet is displayed. There is only one Stage per applet. The Stage contains static methods that handle loading, updating, and drawing Scenes. Stage also contains methods for getting the height and width of the applet and setting the frame rate.

A Scene is an object that updates the display and handles input from the user. All PulpCore apps must implement at least one Scene.A typical game will have multiple Scenes, each corresponding to a component of the game: a title scene, main menu scene, main game scene, high score scene, help scene, etc.The Scene2D class extends the Scene class and provides commonly used features like Sprite management, layer management (layers are Groups of Sprites; typical layers include the background image(s), player/NPC images, and the GUI), and Timeline management (Timelines control animations). Subclasses should override the following two methods:

load(), which executes when the scene is created, typically where resources are loaded

update(int), which executes once per frame, typically contains game logic, input handling, etc.

Rendering is handled by the drawScene() method; most apps will not override this method.The first Scene loaded by an applet is defined by the "scene" applet parameter (in the HMTL file): <param name="scene" value="MyFirstScene" />

A Sprite is an image together with location information. PulpCore contains a number of Sprite classes:

ImageSprite, a standard sprite with an image that is static (CoreImage) or animated (AnimatedImage)

FilledSprite, a solid-colored rectangle (optionally with a colored border), typically used as background

Label, a sprite that displays text; image-based fonts may be loaded using the CoreFont class

some standard user-interface controls: Button, TextField, Slider

Group, a sprite that is itself a collection of sprites

Sprites are added to a scene using the add() method.

Below is the code for a "Hello World"-style class that illustrates the information above.

Although tools such as NetBeans and Eclipse are quite powerful, this short guide will hopefully help increase the audience of PulpCore users to those who use BlueJ (from http://bluej.org: "an integrated Java environment specifically designed for introductory teaching") and wish to avoid ANT scripts.

Setting up PulpCore in BlueJ

Download the pulpcore zip file from the "downloads" section, and extract all files.

In BlueJ, from the menu bar choose: "Tools" --> "Preferences..." , to bring up the "BlueJ: Preferences" window. In this window, click the "Libraries" tab.

Click the "Add" button, and a new window will appears ("Select directory or jar/zip file"). In this window, find the directory where you extracted the pulpcore files. Within this directory, inside the "build" directory, select the file "pulpcore-applet-release.jar", and click the "Open" button. The "Select..." window will close.

Back in the User Libraries list in the "BlueJ: Preferences" window, there will be a new entry; in the "Location" column you will see the path to the "pulpcore-applet-release.jar" file, and in the "Status" column you will see the phrase "Not Loaded".

In the preferences window, click "OK". A window will pop up with a helpful message ("These changes you have made..."; click "OK".

Quit the BlueJ program, and then restart BlueJ. (This enables the new JAR library to load.)

Because PulpCore uses a JavaScript file to load the applet, we will not use BlueJ's built-in AppletViewer. Instead, we will set up the necessary files manually.

First, make a copy of the "pulpcore-applet-release.jar", rename it to "myArchive.jar", and place it in your BlueJ project directory. Open the JAR file using a program such as 7zip or WinRAR. Copy the "PulpyDemo.class" file from your BlueJ project directory into the JAR file. Close the JAR file.

Create a new ZIP file (again, using either 7zip or WinRAR, for example) called "myAssets.zip". This is where all program assets (images, sounds, etc.) should be placed. For the demo program above to work correctly, this ZIP file needs to contain an image file named "logo.png".

Copy the files "splash.gif" and "pulpcore.js" into your directory. (These are also located in the pulpcore zip file.)

Finally, open your favorite text editing program (such as Notepad++), and create a file called "index.html"; this will be the webpage that loads the applet. Use the following code:

Provided the files myArchive.jar, myAssets.zip, splash.gif, pulpcore.js, and index.html are all in the same directory, the applet should be ready to run. Open "index.html" in a web browser (FireFox is highly recommended), and enjoy!

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